Piston grinding machine



April 14, 1942. c. J. GREEN 2,279,902

PISTON GRINDING MACHINE Filed Aug. 14, 1940 3 Sheets-Sheet 1 CL HRENEEJE'REEA/ April 14, 1942. c. J. GREEN 2,279,902

PISTON GRINDING MACHINE Filed Aug. 14, 1940 5 Sheets-Sheet 2 "W EL. HRE/vcEJE'RE'E/v Muss April 14, 1942. c, GREEN 2,279,902

PISTON GRINDING MACHINE Filed Aug. 14, 1940 s Sheets-Sheet s W C4. HRE/VEEJE'REEN Patented Apr 14,

, 2,279,902 PISTON camnmc MACHINE Clarence-J. Green, Worcester, Mass., :assignor to Norton Company, Worcester, Mass., a corporation of Massachusetts Application August 14, 1940, Serial No. 352,567

12 Claims.

The invention relates to grinding machines, and more particularly to an apparatus for grinding a work piece of a noncircular.crosssection, such as a tapered oval shape on an automotive piston.

One object of the invention is to provide a simple and thoroughly practical apparatus for grinding a work piece to a non-circular shape.

Another object of the invention is to provide a grinding apparatus for grinding a work piece to a tapered non-circular cross-section in which the work piece is oscillated toward and from the grinding wheel by means of a rotatable cam.

A further object of the invention is to provide a grinding apparatus to grind a tapered oval shape on a piston in which the major axis of the oval cross-section is uniform throughout the length of the piston. A further object of. the invention is to provide a piston grinding attachment in which a rock bar controlled by a master cam and follower serves to produce the desired oval shape on a piston'and in which a swivel support for the rock bar is swivelled by means of a cam and follower angularly to shift the. axis of the piston being ground to produce a tapered oval surface on the piston being ground.

Another object of this invention is to provide a piston grinding attachment in which the piston being ground is supported on a pivotally mounted rock bar which is rocked about an axis substantially parallel to the axis of the grinding wheel and in which the pivotal support for the rock bar I is pivotally supported to swivel about an axis substantially normal to the axis of the rock bar so as to produce a tapered .oval or elliptical shape on the piston being ground. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and" the scope of the application of which will be indi-- cated in the following claims.

In the accompanying drawings, in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. l is a front elevation of a grinding machine having the improved piston grinding attachment mounted thereon and shown in section;

Fig. 2 is a fragmentary plan view, on an enlarged scale, of the piston grinding attachment as shown in Fig. l; a

Fig. 3 is a fragmentary phantom view of the master cam and follower roller for rocking the rock bar and the master cam and followerv roller for swivelling the rock bar;

Fig. 4 is a fragmentary view showing the adjustable pivotal support for the piston grinding attachment;

Fig. 5 is an exaggerated end elevation of a tapered oval-shaped piston ground by this attachment;

Fig. 6 is a fragmentary plan view, on an enlarged scale, showing the relative positionsof the grinding wheel, tapered piston and vertical pivotal support for the piston grinding attachment;

modified pivotal adjustment shown in Fig. 7.

tudinally movable table II on the usual V-way i that shown in the expired U. S. patent to Norton,

A grinding machine'embodying this invention may comprise a base III which supports a longiciprocating movement. relative to the base III. A motor driven headstck I2 is mounted on the table II and is arranged rotatively to drive a work piece supported by the piston grinding attachment to be hereinafter described.

A transversely movable rotatable grinding wheel I4 is rotatably supported on a transversely movable slide l5 of the type such as, for example,

and flat way (not shovgn) for a longitudinal re- No. 762,838 dated June 14, 1904. In the preferred form, an electric motor I6 is mounted on the upper surface of the, wheel slide l5 and is provided with a driving pulley H which is preferably of the multiple V-groove type which'is connected by a. multiple V-belt l8 with a multi V.-gro0ve pulley I 9 which is mounted on the right-hand end of a wheel spindle 20.

The headstock I2 is preferably a motor driven headstock in which an electric motor 22 is mounted on the upper surface of the headstock 12. The motor 22 is provided with a multi V-groove pulley 23 which is connected by multiple V-belts 24 with a multi V-groove pulley 25 supported on the left-hand end of the headstock spindle 26.

The machine illustrated 'in the present application is substantially the same as that shown in the prior U. S. patent to C. H. Amidon, No. 2,113,363 dated April 5, 1938, to which reference may be had for details of disclosure not contained herein. The table It may be traversed longitudinally by means of a hydraulically operated mechanism controlled by means of a stop a and start lever 30 mounted on the front of the machine base II. A reversing lever 3| may be actuated by table dog's (not shown) to reverse the direction of movement of the table II so as to control the length of its reciprccatory stroke.

The lever 3| controls a reversing valve (not identical in construction with that shown in the above-mentioned prior patent to Amidon.

The table ll may be traversed longitudinally to position a work piece relative to the grinding wheel I by means of a manually operable table traverse mechanism including a manually operable hand wheel 32 which is rotatably supported on the front of the machine base It and which is connected by gearing (not shown) with a rack bar depending from the table i I in a manner substantially the same as that shown in the abovementioned prior patent to Amidon, to which reference may be had for details of disclosure not contained herein.

The transversely movable wheel slide II is supportedon the usual V-way and flat way (not shown) and a wheel feeding mechanism of the nut and screw type is provided which is actuatedby means of a manually operable feed wheel 35 base ll. The details of the nut and screw feed hand end of the swivel support ll. Opposed rows of balls and 56 are interposed between the bracket SI and a bracket 51 which is fixedly sup-' rotatable work support which is arranged for a controlled transverse movement relative to the operative face of the grinding wheel. To accomplish this result, a rock bar it is supported in bearings II and 62 which are in turn fixedly supported on the swivel-frame 40. The rock bar ll serves rotatably to support a work piece, such as a piston 63; Aheadstock or master cam spindle 64 is rotatably supported in bearings 65 and I! which are carried by brackets $1 and 68. The

brackets 61 and 68 are fixedly mounted on the rock bar 80; The spindle 64 serves asa support for a piston supporting and driving head it which'supports the headstock or open end of the piston 03. The footstock 10 is fixedly mounted rotatably supported on the front of the machine mechanism have not been shown in the present application, since they are not considered to be a part of the present invention.- For further details of the, wheel feeding mechanism, reference may be had to the above-mentioned expired patent to Norton, No. 162,838. Y

The machine; as previously" described, is substantially the sameas that shown in the prior patent to Amidon; No. 2,113,363, to which refer ence may be had fordetails of disclosure not contained herein. A piston grinding attachment I is provided which may be readily supported on:

the work supporting table II. The piston grinding attachment may comprise a pivotally mounted supporting frame ll which is supported to pivot about a substantially vertically posi tioned stud II. The stud 4| is supported by an adjustably positioned bracket 42 which is adjustably supported onthe table II. A clamping screw 43 passes through an elongated slot ll in the bracket 42 and is screw threaded into the table II. It will be readily apparent from the foregoing disclosure that the bracket 42 may be adjusted to vary the position of the pivot stud relative to the table I I. A bracket 45 is fixedly supported onthe upper end ofthe pivot, stud I l and is adjustably clamped to the under surface of the frame 40 by means of a clamping screw 46 which passes through an elongated slot 41' in the bracket 45 and is screw threaded into the bracket 40. By adjustment of the frame ll relative to the bracket", the pivotal axisof the frame may be varied as desired.

. In order that the frame ll may be readily swiveled anti-friction supporting bearings are provided adjacent to the opposite ends thereof. An arcuate-shaped bracket of substantially L- shaped cross section 5| depends from the lefthand end of the swivel frame 40; A row of balls 52 and 53 are interposed between the bracket 5|] and a bracket 54 supported on the table II. Similarly, an arcuate bracket SI of substantially L-shaped cross-section depends from the rightthe right-hand end of a piston s: to be ground.

In order to produce-a predetermined oval or elliptical shape on the piston 83, it is desirable to impart a rocking or oscillating movement to the rock bar 6.. This is preferably accomplished by providing a master cam 15 on the headstock or master cam spindle 64. The periphery of the master cam 15 is engaged by a rotatable follower roller-16 which is rotatably supported on a stud 11. The stud isfixediy supported ina frame II which isfmounted in fixed relation with the table II The master cam 15 is accurately shaped so as to produce the desired and predetermined oval or elliptical shape on the periphery of the piston 63. If desired, the master cam 15 may be interchanged-for a master cam of a different shape in setting up the attachment for grinding diflerent sizes and shapes of pistons. U

It will be readily apparent from the foregoing disclosure that a rotary motion of the master cam spindle M and the master cam 15 which is in operative engagement with the master cam roller 66 will imparta rocking motion to the rock bar 6 0 to rock the piston 63 transversely toward and from the operative peripheral surface" of .the grinding wheel ll to generate the desired and predetermined oval or elliptical shapethereon. The headstock spindle 2 is connected by means of a universal joint "a with the left-hand end of the spindle 64. When the motor 22 is rotated to impart a rotary motion to the headstock spindle ,2, this motion will be transmitted through the universal joint a to rotate the headstock or master cam spindle it which through the master cam 15 will impart a controlled rocking or oscillating movement of the rock bar "to rock the axis of the piston 88 being ground toward and from the periphery of the grinding wheelthe oscillating movement of the rock bar, ll so amaaoa that a tapered oval or elliptical surface maybe left-hand end of the rock bar 88 (Fig. 1). -A

sprocket 82 is formed integral with the sleeve 8I.- A link chain 83 drivingly connects the sprocket 82 with a sprocket 84 which is supported adjacent to the left-hand end of the master cam or headstock spindle 84. The sprocket 84 is preferably adjustably mounted on the shaft 84 and may be locked in adjusted position thereon by a pair of collars Wand 88 which are screw threaded on the end portion of the spindle 84.

The adjustable mount for .the sprocket 84 serves to facilitate timing of the taper cam 88 relative to the master cam I5. If it is desired to adjust the relationship of the cam 88 relative to the master cam 15, one or both of the collars 85 and 88 may be loosened and the sprocket 84 rotated to angularly adjust the position of the cam 88, after which the collars 85 and 88 may again betightened to lock the cam 88 in timed relation with the cam I5.

A follower roller 88 is arranged peripherally to engage the cam 88. Theroller 88 is rotatably supported on a stud 88 which is in turn supported by a yoke-shaped bracket 88. The bracket 88 is preferably pivotally mounted so that it may swivel about a vertical axis whereby its peripheral face may be maintained in alignment with the peripheral face of the cam 88 during the oscillating movement of theframe 48. The bracket 88 is provided with a downwardly extending, cylindrically shaped integral stud 9| which fits within a bushing 82 which is held in fixed relation with the frame 93 which is fixedly supp rted on the table II.

A yieldable device is provided for maintaining the taper forming cam 88 in operative engagement with the follower roll 88 during the grinding operation. As illustrated in Fig. 2, a spring 95 of the tension type is interposed between a stud 98 which is fixedly mounted on the frame 48 and a stud 91 which is fixedly supported on the table II. The tension of the spring is sufficient to maintain the cam 88 in operative engagement with the roller 88 so that as the cam 88 is rotated against the roller 88, the axis of which is fixed, an oscillating motion will be transmitted to the frame 48 during the grinding operation to grind the desired oval-shaped taper on the piston 83.

Similarly, a yieldable device is provided for maintaining the master cam I in operative engagement with its follower roller I8 during the grinding operation. As shown in Fig. 3, a tension spring I88 is interposed between an arm I8I which is formed integral with the bracket on the rock bar 88 and a stud I82 which is fixedly mounted on the upper surface of the work table II. It will be readily apparent from the fore going disclosure that when the headstock spindle 28 is rotated by the motor 22, a rotary motion will be imparted to the master cam spindle 84 to oscillate the rock bar 68 and thereby produce a predetermined oval or elliptical shape on the work piece and at the same time. through the taper forming the cam'88 and the follower roller 88, an oscillating'movement will be imparted to the frame 48 about its pivot stud M to produce the desired elliptical taper on the periphery of the cam 63.

In grinding a tapered oval on the piston 83, it may be desirable to provide a slight oval shape to the piston which tapers toward the open end 1 tudinal adjustment thereof.

of the piston, in which the long axis of the oval remains constant throughout the length of the piston. In such a case, it is'desirable to locate the axis of the pivot stud 4| as indicated diagrammatically in Fig. .6 by a small circle I84 adjacent to the line of contact between the grinding wheel I4 and the piston 88 and at 'apoint adjacent to the right-hand end of the piston 83.

To facilitate setting up the machine for grinding a piston in the above manner, the pivot stud H has been illustrated in Figs. 2 and 4 as being adjustable transversely relative to the table II. In case the machine is to be utilized for grinding several types and sizes of pistons, it may be desirable to provide not only a transverse adjustment for the pivot stud 4| but also a longi- A modified pivot adjustment has been illustrated in Figs. 7 and 8 in which a pivot stud I85 may be adjusted both transversely and longitudinally so that its axis may be aligned and located in the position I84,

as indicated in Fig. 6, or 'in any other desired position, depending upon the shape of the piston to be ground.

As indicated in Figs. '1 and 8, the swivel bracket 48 may be provided with a dovetailed slideway I88 which mates with a correspondingly shaped way formed on a longitudinally adjustable slide member I81. One or more clamping screws I88 are provided for clamping the slide I81 in adjusted position with the way I88, The longitudinally adjustable slide member I8! is provided with a transversely extending dovetailed slideway I88 which mates with a correspondingly shaped slideway formed in arm II8 which supports the pivot stud I85. Binding screws III and II! are provided for clamping the transversely adjustable slide member I81 in adjusted position relative to the arm II 8.

Similarly, the table II is provided with an upwardly projecting dovetailed slideway II3 which extends longitudinally relative to the table II. A longitudinally adjustable slide II4 is provided with a dovetailed slideway which mates with the way II3. A clamping screw H5 is provided for clamping the longitudinally adjustable slide H4 in adjusted position relative'to the table I I. The longitudinally adjustable slide H4 is provided with a transversely extending dovetailed slideway II8 which mates with a correspondingly shaped way in an arm I". The arm H1 is provided adjacent to its right-hand end (Fig. 7) with a bushing .8 which mates with the pivot stud I85. Clamping screws H9 and I28 are provided' for clamping the longitudinally adjustable slide H4 in its adjusted position relative to the arm 1.

It will be readily apparent from the foregoing disclosure that the axis of the pivot stud I85 may be adjusted both longitudinally and transvers'ely relative to the table II and also relative to the pivotally supported frame 48 which supports the rocking bar. By utilizing this construction. the axis of the pivot stud I85 may be adjusted into the desired relationship both longitudinally and transversely so that the pivot point for producing the taper on the piston to be ground may be located in a desired and predetermined re'ationship with the surface to be ground.

The taper produced on the piston as well as the extent of the oval produced thereon may be only a few thousandths of an inch. This relationship has been materially exaggerated in Figs. 5 and 6' to clarify the illustration. As shown in Fig. 5, the oval or elipse A, C, B, D is the oval produced .disclosure that practically' anyfdesired shape,

either oval, elliptical or otherwise, may be produced on the periphery of a work piece, suchas the piston 63, and any taper either uniform or otherwise may be producedby providing a master cam I5 and a taper, producing cam ll of the required shape andsize. Thecam 80 may be readily timed with the cam so as to coordinate the rocking of the rock bar ill and the oscillation of the pivotally supported frame 40 so that the desired and predeterminedshape maybe produced on the peripheral surface of the work piece 63. I

' The operation of this machine will be readily apparent from the foregoing disclosure. Assuming the proper cams I5 and 80 havebeen placed in the machine and the taper producing cam 80 timed in the desired relationship with the master cam 15, and assuming also the axis of pivot stud llor I05 to have been previously adjusted .into the desired location such as, for

port about an as s bstantially parallel to the axis of the grinding heel, said cam and follower serving to determine the cross-sectional example, that shown in the diagram (Fig. 6), a

piston 63 is placed in position between the piston holder 69 on thejmaster cam spindle and the footstock center II. The motor 22 is then started to produce a rotary motion of the work piece 63 and at the same time to oscillate the rock bar 60 and to swivel the. pivotally mounted frame 40. The grinding 'wheel I4 is fed forward into grinding position by means of the manually operable feed wheel '-35'and the piston I is ground during the combined rocking movement of the rock bar 80 and the oscillation of the frame 40 to produce a peripheral surface on the piston 63 in the form of a tapered oval shape. If it is desired to grind a piston of a slightly different shape, the cams 15 and ll may be readily replaced by master cams of the desired shape and size and the pivot studs 4| or I05 again adjusted into the desired operating position.

It ,will thus be seen that there has been provided by this invention apparatus in which the various objects hereinbefore set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood ing means and cam, an oscillatable platen interthat all matter hereinbefore set forth or shown in the accompanying drawings is to be. interpreted as illustrative and not in a' limiting sense.

I claim:

1. In a grinding machine having a base, a rotatable grinding wheel, a transversely movable rotatable work support, means including a mas-.- ter cam and a, follower to impart a transverse movement to said work support, an oscillatable platen to support said work support which is oscillatable about an axis normal to said transverse movement, and means including a cam and a follower to oscillate said work support about an axis substantially parallel to the axis of the grinding wheel during the transverse movement of the work support. I

2. In a grinding machine having a base, a

transversely movable rotatable work support,

means including a master cam and a follower to shape of a work piece, an oscillatable member to support said work support, and means including a cam and a follower to'oscillate said memberand work support during the transverse movement thereof about an axis normal to said transverse movement, said latter cam land. follower serving to determine the extentof taper, produced on a work piece.

3. In a grinding machine having a base, a rotatable grinding wheel, a transversely movable rotatable work support, work driving meanson said support, means includinga movable master cam and a follows: to impart a transverse movement to said work support about an axis substantially parallel to the axis of the grinding 'wheel, means to synchronize the work driving means and cam, an oscillatable platen, a rotatable work support including headstock and footstock centers to support said work support, a movable cam and a follower to oscillate said platen about an axis normal to said transverse movement, and driving means tosynchronize the Y movement of said cams so as to produce a tapered ovalshape on a work" piece.

4. In a grinding machine having a base, a transversely movable rotatable grinding wheel, a longitudinally movable work table, a transversely movable rotatable work support on said table, work driving means on said support, means including a rotatable master cam and a follower to impart a transverse movement to said work support, means to synchronize the work drivposed between the table and work support, a rotatable cam and a follower to oscillate said platen,

and driving means tosynchronize the rotation of said cams so as to produce a tapered oval shape onawork piece. 1

5. In a grinding machine having a base, a transversely movable rotatable grinding wheel, a longitudinally movable "work table, an oscillatable platen on said table, a vertically arranged pivotal connection between said table and platen, a transversely movabl rotatable work support on said platen, work driving means on said support, means including a rotatable master cam and a follower to impart a transverse movement to 'said work support, a rotatable cam and a follower to impart an oscillating movement'to said platen, and driving means to synchronize the work driving means and cams so as to produce a tapered oval shape on a work piece.

6. In a grinding machine having a base, a

transversely movable rotatable grinding wheel, a

to adjust the position of said pivot stud relative to said table and platen. j v

7. In a grinding machine' having a base, a transversely movable rotatable grinding wheel, a longitudinally movable work table, anoscillatable platen on said table, an adjustable vertical pivot stud interposed between said table and platen,

a transversely movable rotatable work support on said platen, work driving means on said support, means including a rotatable master cam and a follower to impart a transverse movement to said work support, a rotatable cam and a follower to impart an oscillating movement to said platen, synchronous driving connections between the work driving means and said cams, and a transverse adjusting means for said pivot stud to facilitate a transverse adjustment of the pivotal axis of the platen relative to the operative face of the grinding wheel.

8. In a grinding machine having a base, a transversely movable rotatable grinding wheel, a longitudinally movable work table, an oscillatable platen on said table, an adjustable vertical pivot stud interposed between said table and platen, a transversely movable rotatable work support on said platen, work driving means on said support, means including a rotatable master cam and a follower to impart a transverse movement to said work support, a rotatable cam and a follower to impart an oscillating movement to said platen, synchronous driving connections between the work driving means and said cams, and a longitudinal adjusting means for said pivot stud to facilitate a longitudinal adjustment of the pivotal axis of the platen relative to the operative face of the grinding wheel.

9. In a grinding machine having a base, a transversely movable rotatable grinding wheel, a longitudinally movable work table, an oscillatable platen on said table, an adjustable vertical pivot studinterposed-between said table and platen, a transversely movable rotatable work support on said platen, work driving means on said support,

means including a rotatable master cam and afollower to impart a transverse movement to said work support, arrotatable cam and a follower to impart an oscillating movement to said platen, synchronous driving connections between the work driving means and said cams, and a longitudinal and transverse adjusting means for said pivot stud to facilitate adjustment of the pivotal axis of the platen relative to the operative face of the grinding wheel.

10. In a grinding machine having a base, a transversely movable rotatable grinding wheel, a longitudinally movable work table, a pivotally mounted rock bar on said table, a rotatable work support on said rock bar, work driving means thereon, means including a master cam and a follower roller to rock said bar, an oscillatable supporting platen interposed between the rock bar and table, an adjustable vertical pivotal connection between said platen and table, means to adjust the position of said pivotal connections, and means including a master cam and follower roller interposed between the table and platen to oscillate said platen during the oscillation of the rock bar so as to produce a tapered oval shape on a work piece.

11. In a grinding machine having a base, a transversely movable rotatable grinding wheel, a longitudinally movable work table, an oscillatable platen on said table, an adjustable vertical pivot stud between the table and platen, a rock bar on said platen, a rotatable work support on said rock bar, a work driving means therefor, a rotatable master cam and a follower roller to rock said bar, a rotatable cam and a follower to oscillate said platen, and synchronous driving connections between the work driving means and said cams so as to impart a combined rockin and oscillating movement of said work support to produce a tapered oval on a work piece.

12. In a grinding machine having a base, a transversely movable rotatable grinding wheel, a work table, an oscillatable platen on said table, a vertical pivot stud between the table and platen, a rotatable work support, horizontal pivotal connections between said platen and work support, a

, work driving means, a rotatable master cam and a follower to rock said work support, synchronous driving connections between the work driving means and master cam, a rotatable cam and a follower to oscillate said platen, synchronous driving connections between said master cam and said rotatable cam, and adjustable means to time the rotatable cam relative to the master cam.

CLARENCE J. GREEN. 

